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Solar electric power generation utilizing photovoltaic (PV) modules is associated with low electrical efficiency that substantially decreases as its surface temperature exceeds an appropriate limit, particularly in hot climate regions. Consequently, it is required to keep PV modules relatively under a condition of low temperature using a cooling system as possible. The present experimental study evaluates the performance of the combined photovoltaic thermal (PV/T) module employing a water cooling system attached to the back surface during June for the city of Sohag in Egypt. The experimental results show that utilizing a water cooling system decreases the average surface temperature of the PV module from 44.8 °C to 30.3 °C on the back side and from 46.6 °C to 36.9 °C on the front side. The maximum value of the thermal heat gain of the PV/T module that is maintained at noon equals 230 W, and the corresponding value of the electrical power output is 34.4 W. Furthermore, the electrical efficiency of the PV/T module is 8% higher than that of the PV module without a water cooling system. Finally, the maximum and average values of the overall efficiency of PV/T module are 76.4% and 68.9%, respectively. [ABSTRACT FROM AUTHOR]

In this study, the cooling of a gas turbine (GT) blade leading edge using a single row of five impinging air jets was numerically and experimentally investigated. The inner surface of the blade leading edge was depicted as a semicircle profile. The numerical study was performed using a shear stress transport (SST) k-ω turbulence model. On the other side, the experimental work was conducted using the infrared (IR) thermal camera. Additionally, the heat transfer characteristics were investigated with changing the Reynolds number (⁠Re ⁠) from 5000 to 40,000. The study was carried out for different cases based on the jet diameter (⁠d ⁠), named as fixed diameter (FD) and variable jet diameter in the streamwise flow direction, i.e., ascending diameter (AD) and descending diameter (DD). The local and average Nusselt numbers and heat transfer uniformity were studied at different operating and design parameters. The results revealed that for FD, increasing the jet diameter decreased the average Nusselt number while it enhanced the heat transfer uniformity. Furthermore, for all values of Re ⁠, the thermal performance of the AD was better than the DD, which has the worst heat transfer uniformity. Finally, predicted developed correlations to estimate the average Nusselt number, surface heat transfer uniformity, and performance evaluation factor (PEF) for all cases of jet diameter were introduced. [ABSTRACT FROM AUTHOR]